>perl -wle"print '1/2'+0"
Argument "1/2" isn't numeric in addition (+) at -e line 1.
1

>perl -wle"print '1abc'+0"
Argument "1abc" isn't numeric in addition (+) at -e line 1.
1

>perl -wle"print '123/456'+0"
Argument "123/456" isn't numeric in addition (+) at -e line 1.
123

##</code><code>##

>perl -MMath::BigRat -wle"print Math::BigRat->new('1/2')->numify();"
0.5